There are many types of data. For example, we need to handle data such as names, adresses, money, date, stock quotes, statistics and etc everyday. Similarly In Visual Basic, we are also going to deal with these kinds of data. However, to be more systematic, VB divides data into different types.

• Numeric Data

  Numeric data are data that consists of numbers, which can be computed mathematically with various standard operators such as add, minus, multiply, divide and so on. In Visual Basic, the numeric data are divided into 7 types,

  Type	Storage	Range of Values
  Byte	1 byte	0 to 255
  Integer	2 bytes	-32,768 to 32,767
  Long	4 bytes	-2,147,483,648 to 2,147,483,648
  Single	4 bytes	-3.402823E+38 to -1.401298E-45 for negative values 1.401298E-45 to 3.402823E+38 for positive values.
  Double	8 bytes	-1.79769313486232e+308 to -4.94065645841247E-324 for negative values 4.94065645841247E-324 to 1.79769313486232e+308 for positive values.
  Currency	8 bytes	-922,337,203,685,477.5808 to 922,337,203,685,477.5807
  Decimal	12 bytes	+/- 79,228,162,514,264,337,593,543,950,335 if no decimal in use, +/- 7.9228162514264337593543950335 (28 decimal places).

  Numeric Data Types
• Non-numeric Data Types

  Data Type	Storage	Range
  String(fixed length)	Length of string	1 to 65,400 characters
  String(variable length)	Length + 10 bytes	0 to 2 billion characters
  Date	8 bytes	January 1, 100 to December 31, 9999
  Boolean	2 bytes	True or False
  Object	4 bytes	Any embedded object
  Variant(numeric)	16 bytes	Any value as large as Double
  Variant(text)	Length+22 bytes	Same as variable-length string

  Nonnumeric Data Types

Literals are values that you assign to a data. In some cases, we need to add a suffix behind a literal so that VB can handle the calculation more accurately. For example, we can use num=1.3089# for a Double type data. Some of the suffixes are displayed in the table below

In additon, we need to enclose string literals within two quotations and date and time literals within two # sign. Strings can contain any characters, including numbers. The following are few examples:

memberName="Turban, John."
TelNumber="1800-900-888-777"
LastDay=#31-Dec-00#
ExpTime=#12:00 am#

Variables are like mail boxes in the post office. The contents of the variables changes every now and then, just like the mail boxes. In term of VB, variables are areas allocated by the computer memory to hold data. Like the mail boxes, each variable must be given a name. To name a variable in Visual Basic, you have to follow a set of rules.

The following are the rules when naming the variables in Visual Basic

• It must be less than 255 characters
• No spacing is allowed
• It must not begin with a number
• Period is not permitted

In Visual Basic, one needs to declare the variables before using them by assigning names and data types. They are normally declared in the genaral section of the codes' windows using the Dim statement.
The format is as follows:

Dim variableNmae as DataType

Dim password As String
Dim yourName As String
Dim firstnum As Integer
Dim secondnum As Integer
Dim total As Integer
Dim doDate As Date

Dim password As String, yourName As String, firstnum As Integer,....

For string declaration, there are two possible formats, one for the variable-length string and another for the fixed-length string.
For the variable-length string, just use the same format as above. However, for the fixed-length string, you have to use the format as shown below:

Dim VariableName as String * n,
where n definex the number of characters the string can hold.

Dim yourName as String * 10